Actions of Muscles

Question 1

latissumus dorsi (3)

Answer 1

shoulder extension, adduction, IR

Question 2

upper trapezius bi/uni (5)

Answer 2

bi:
head/neck– extension

uni:
head/neck–
lateral flexion
contralateral rotation

scapula–
elevate
upwardly rotate

Question 3

middle trapezius (2)

Answer 3

scapula:
adduct/retract
stabilize

Question 4

lower trapezius (2)

Answer 4

scapula:
depress
upwardly rotate

Question 5

levator scapulae (2)

Answer 5

scapula:
elevate
downwardly rotate

Question 6

rhomboids (3)

Answer 6

scapula:
adduct/retract
downwardly rotate
fix scapula to thoracic wall

Question 7

splenius bi/uni (3)

Answer 7

bi:
head/neck—
extension
uni:
head/neck—
lateral flexion
ipsilateral rotation

Question 8

erector spinae group bi/uni (2)

Answer 8

bi:
spine– extension
uni:
spine– ipsilateral flexion

Question 9

rotatores bi/uni (2)

Answer 9

bi:
spine– extension
uni:
spine– contralateral rotation

Question 10

multifidus bi/uni (3)

Answer 10

bi:
spine– extension
uni:
spine–
contralateral rotation
stabilize

Question 11

semispinalis bi/uni (2)

Answer 11

head/neck/spine–
bi: extension
uni: contralateral rotation

Question 12

rectus capitis posterior major and minor (2)

Answer 12

head–
extension
ipsilateral rotation

Question 13

obliquus capitis superior bi/uni (2)

Answer 13

head–
bi:
extension
uni:
ipsilateral flexion

Question 14

obliquus capitis inferior (1)

Answer 14

head– ipsilateral rotation

Question 15

deltoid (clavicular) (2)

Answer 15

shoulder–
flexion
IR

Question 16

deltoid (acromial)

Answer 16

shoulder– abduction

Question 17

deltoid (spinal) (2)

Answer 17

shoulder–
extension
ER

Question 18

pectoralis major (both heads) (3)

Answer 18

shoulder–
adduct
IR
horizontal adduction

Question 19

pectoralis major (clavicular) (1)

Answer 19

shoulder–
flexion

Question 20

pectoralis major (sterno) (1)

Answer 20

shoulder–
extension

Question 21

pectoralis minor (2)

Answer 21

scapula–
stabilizes scapula against thoracic wall
thorax–
elevates during inhalation

Question 22

teres major (3)

Answer 22

shoulder–
adduct
extension
IR

Question 23

supraspinatus (2)

Answer 23

shoulder–
abduction
stabilizes head of humerus

Question 24

infraspinatus (2)

Answer 24

shoulder–
ER
stabilizes head of humerus

Question 25

teres minor (2)

Answer 25

shoulder–
ER (helper)
stabilizes head of humerus

Question 26

subscapularis (2)

Answer 26

shoulder–
IR
stabilizes head of humerus

Question 27

serratus anterior (2)

Answer 27

scapula–
protract
stabilizes scapula against thoracic wall

Question 28

sternocleidomastoid bi/uni (4)

Answer 28

uni:
head/neck–
ipsilateral flexion
contralateral rotation

bi:
head/neck–
extension (at OA joint)
flexion (cervical)
extension of superior cervical AND flexion of inferior vertebrae

Question 29

platysma

Answer 29

frown
draws skin of neck superiorly

Question 30

external intercostals

Answer 30

draws ribs up with inhalation

Question 31

internal intercostals

Answer 31

draws ribs down with exhalation

Question 32

diaphragm

Answer 32

increases volume in thoracic cavity during inhalation

Question 33

quadratus lumborum (4)

Answer 33

bi: fix last rib during forced inhalation

uni:
pelvis–
laterally hike
spine–
ipsilateral flexion
ipsilateral extension

Question 34

psoas major (4)

Answer 34

trunk–
balance
flexion (acting inferiorly with iliacus)

hip–
flexion (acting inferiorly with iliacus)

spine–
lateral flexion (acting superiorly)

Question 35

iliacus (2)

Answer 35

hip–
flexion
stabilizes hip joint
*acts with psoas major

Question 36

rectus abdominis (3)

Answer 36

spine–
flexion

pelvis–
posterior tilting

abdominal viscera–
compression

Question 37

external oblique bi/uni (3)

Answer 37

spine–
bi:
flex
compress abdominal contents
uni:
lateral flexion
contralateral rotation

Question 38

internal oblique bi/uni (4)

Answer 38

spine–
bi:
flexion
compress abdominal contents
uni–
lateral flexion
ipsilateral rotation